Update: Rewrite of column type detection

- Automatic column type detection was a real weak point of v1.9- - it
  did basically work, but if you then updated a row that didn't match
  the current data type it would always end up as a string. A good
  example of this is the ambiguous date "06-06-13" (is it dd-mm-yy or
  mm-dd-yy?). If it was detected as dd-mm-yy and then you add '05-20-13'
  to the column (or update an exisiting cell), the type would not match
  the exisiting value that thus failover to a string.

- Type detection is now more rigorous, but still optimised (since it
  has the potential to take up a significant amount of time). When a row
  is added or updated, or a cell is updated, the exisiting type is
  removed from the target column(s) and then, before sorting or
  filtering, the _fnColumnTypes function checks to see if any column
  needs to be type detected and do so if needed. This approach allows
  multiple rows to be added (for example) before the draw is performed and
  the type actually needs to be calculated.

- In future I'd like to have a 'data-ready' type event which will tell
  DataTables, and any of its components that something wants to work with
  the data in the table and it should prep the data. The counterpart would be
  a 'data-invalid' flag which would be set on update, add etc so it knows
  when an update is needed.
Size: Remove `_fnColumnOrdering` and replace with a _pluck call
Dev styling - darken the paging button border slightly
Update: If there is no sorting methods for the column type, use string

- In the case of filtering, if there is no filtering extension for the
  column type, then the basic string based filter formatting is
  performed (i.e. string is always the fallback - there can't be an
  error because a function isn't there).

- This commit matches that behaviour in sorting. If you define a column
  type as something for which there is no column sorting function, then
  the string type will be used rather than resulting in a javascript
  error.
Fix: A default for mData would not have been applied

- Fix for DataTables/DataTables issue #212
New: Currency, formatted numbers and HTML numbers sort types built in

- This commit sees the number of built in type detection and sorting
  functions increase to cover the most common cases of use of plug-ins
  for DataTables (witht he exception of dates, for which a new first
  class plug-in will be created). Specifically, DataTables now has built
  in support for:
  - Dates (Date.parse())
  - Numeric sorting
  - Formatted numbers sorting (including currency and thousands
    seperators)
  - Numbers wrapped in HTML (link tags for example)
  - Formatted numbers in HTML
  - HTML

Although the numeric sorting plug-ins could have been collapsed down to
just two plug-ins (rather than 4) I decided to do it this way to allow
type based filter formatters to be used with the formatted number types
to allow search for "100,000" or "100000" to match the same data. This
is not built in, but it is possible (and might be in future).

- The goal with these additional functions is to enhance the abilities
  of DataTables out of the box to cover the most common cases for data
  usage - DataTables is all about making data in tables more accessable
  after all! The size cost is ~300 bytes for these additional functions